What is homeopathy?

It is based on a series of ideas developed in the 1790s by a German doctor called Samuel Hahnemann.

A central principle of the "treatment" is that "like cures like" – that a substance that causes certain symptoms can also help to remove those symptoms. A second central principle is based around a process of dilution and shaking, called succussion.

Practitioners believe that the more a substance is diluted in this way, the greater its power to treat symptoms. Many homeopathic remedies consist of substances that have been diluted many times in water until there is none or almost none of the original substance left.

Homeopathy is used to "treat" an extremely wide range of conditions, including physical conditions such as asthma and psychological conditions such as depression (see When is it used?).

Does it work?

There has been extensive investigation of the effectiveness of homeopathy. There is no good-quality evidence that homeopathy is effective as a treatment for any health condition (see What can we conclude from the evidence?).

It is available on the NHS?

Homeopathy is not available on the NHS in all areas of the country. Two NHS hospitals provide homeopathy, and some GP practices also offer it.

Homeopathy is usually practised privately and homeopathic remedies are available from pharmacies. The price for an initial consultation with a homeopath can vary from around £20 to £80. Homeopathic tablets or other products usually cost around £4 to £10.

What should I expect if I try it?

When you first see a homeopath they will usually ask you about any specific health conditions, but also about your general wellbeing, emotional state, lifestyle and diet.

Based on this, the homeopath will decide on the course of treatment, which most often takes the form of homeopathic remedies given as a pill, capsule or tincture.

Your homeopath may recommend that you attend one or more follow-up appointments so the effects of the remedy on your health can be assessed.

When is it used?

Homeopathy is used for an extremely wide range of health conditions. Many practitioners believe that homeopathy can help with any condition.

Among the most common conditions that people seek homeopathic treatment for are:

asthma

ear infections

hay fever

mental health conditions, such as depression, stress and anxiety

allergies, such as food allergies

dermatitis (an allergic skin condition)

arthritis

high blood pressure

There is no good quality evidence that homeopathy is an effective treatment for these or any other health conditions.

Some practitioners also claim that homeopathy can prevent malaria or other diseases. There is no evidence to support this and no scientifically plausible way that homeopathy can prevent diseases.

Is it safe?

Homeopathic remedies are generally safe and the risk of a serious adverse side effect arising from taking these remedies is thought to be small.

Some homeopathic remedies may contain substances that are not safe, or that interfere with the action of other medicines. You should talk to your GP before stopping any treatment prescribed by a doctor or avoiding procedures such as vaccination in favour of homeopathy.

What can we conclude from the evidence?

There have been several reviews of the scientific evidence on the effectiveness of homeopathy. The House of Commons Science and Technology Committee said there is no evidence that homeopathy is effective as a treatment for any health condition.

There is no evidence for the idea that substances that can induce certain symptoms can also help to treat them. There is no evidence for the idea that diluting and shaking substances in water can turn those substances into medicines.

The ideas that underpin homeopathy are not accepted by mainstream science, and are not consistent with long-accepted principles on the way that the physical world works. The Committee's 2010 report on homeopathy said the "like cures like" principle is "theoretically weak", and that this is the "settled view of medical science".

It is of note, for example, that many homeopathic remedies are diluted to such an extent that there is unlikely to be a single molecule of the original substance remaining in the final remedy. In cases such as these, homeopathic remedies consist of nothing but water.

Some homeopaths believe that, due to the succussion process, the original substance leaves an "imprint" of itself on the water. But there is no known mechanism by which this can occur. The 2010 report said: "We consider the notion that ultra-dilutions can maintain an imprint of substances previously dissolved in them to be scientifically implausible."

Some people who use homeopathy may see an improvement in their health condition due to a phenomenon known as the placebo effect.

If you choose health treatments that provide only a placebo effect, you may miss out on other treatments that have been proven to be more effective. Read more about the placebo effect.